Dunham-Bush ACXi 165-5SP-LN, Installation, Operation And Maintenance Manual

5.0 MAINTENANCE

5.6 ELECTRICAL

MALFUNCTION

The unit has four devices designed to protect
compressor motors and manual motor controllers
from electrical malfunctions: Circuit breakers,
starter overload relays, under voltage relay, and
motor over temperature protectors (optional).

If the under voltage relay trips, it is a sign of
trouble in incoming power. If it trips again after
resetting, call your electric utility to investigate
the problem. If circuit breaker or motor overload
relay or motor over temperature  protectors trip,
this is a sign of possible motor trouble. DO NOT
reset and try to run compressor again. Call
authorized service representative to check for
motor trouble. Resetting these safety devices and
repeated starting could turn a minor motor
problem into a costly major motor burnout.

5.7 REFRIGERANT CHARGE

5.7.1 GENERAL

All packaged chiller units are given a
complete charge of refrigerant at the
factory. The type and amount of
refrigerant required is in Physical
Specifications. The total refrigerant
shown is for the entire system. Since
these units have separate circuits, each
circuit should be considered separately for
charging.
In order to check proper refrigerant
charge, look in each liquid line sight glass
with the aid of a flashlight during system
operation. At all operating conditions, the
sight glass should be clear. If bubbles are
visible at any operating condition, the
circuit is short of charge.

Be careful not to overcharge the machine.
Overcharging will result in considerable

liquid logging in the condenser, and
excessive condensing pressure.

To add refrigerant, connect a refrigerant
vessel to the 1/4" back seating port of the
suction valve. Purge the air from the tube
with refrigerant gas before connecting.
With the unit running, open the
refrigerant vessel vapor connection
slightly. If the refrigerant vessel is
warmer than the evaporator, refrigerant
will more readily flow from the vessel
into the unit.

5.7.2 AIR COOLED PACKAGES

To determine the proper refrigerant
charge, check the amount of subcooling if
possible. The amount of subcooling at the
liquid line (liquid line saturation
temperature corresponding to liquid line
pressure minus liquid line temperature)
should be between 15°F and 20°F.
Subcooling at the condenser outlet-
subcooler inlet trap should not exceed
5°F. This sight glass should be clear with
no bubbles.

5.8 OIL CHARGE

The proper oil charge is in the unit as supplied
from the factory. Any operating compressor
should show oil return and oil overflow at all
time. If for some reason, a compressor runs low
on oil, a low oil level switch in the compressor
will shut it down before any damage is done. In
the event of a low oil shutdown, call a D/B
authorized service agent to correct the problem.

DO NOT ADD OIL TO THE SYSTEM.

Note:

 Only  DB 18 oil may be used in this

package. Use of other oil is not approved by
Dunham-Bush, and will result in poor
performance of the package.

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